Journal Article

Balancing Hemorrhage Risk with Electrode Coverage

Speidel, Benjamin, Lee, Anthony T, Fan, Joline, Chang, Edward F, Nichols, Noah M.L, Knowlton, Robert C

2020

Overview

INTRODUCTION Intracranial electrode monitoring is fundamentally important for epilepsy surgery evaluations. Currently, there is an emerging debate over the optimal approach between subdural grids and stereoelectroencephalography (SEEG). Our institution utilizes two strategies for intracranial EEG ictal recordings: 1) a “hybrid” approach, whereby patients receive combined subdural grid and intraoperative neuronavigation-based depth electrode implantations, and 2) SEEG. METHODS A retrospective review was performed on consecutive patients that underwent hybrid or SEEG implantation from July 2012 to July 2019. Intracranial recordings were utilized in patients with putative seizure onset regions that were MR-negative, poorly localized, and/or abutting eloquent cortex. Hemorrhagic and non-hemorrhagic complications, neurological deficit at discharge, success of localizing seizure focus, one-year Engel I outcomes, and electrode locations. RESULTS 99 hybrid and 44 SEEG procedures were performed. Hemorrhagic complication rates were similar (SEEG: 8%; hybrid: 7.1%, P = .96). SEEG hemorrhages were all intra-axial, whereas hybrid hemorrhages were all extra-axial. Neurological deficits from hybrid cases were quickly reversed with prompt hematoma evacuation, while SEEG was associated with more severe deficits at discharge (P < .01). There was no difference in non-hemorrhagic complications (P = .24). Hybrid cases had higher density of electrode contacts (hybrid: 122.1±28.5, SEEG: 89.8±34.2, P < .01), with more sampling of eloquent cortices. SEEG electrodes were more likely to be located in white matter (SEEG: 34.0%, hybrid: 9.2%, P < .01). CONCLUSION The hybrid and SEEG approaches resulted in similar, relatively low hemorrhage rates in our institutional series. An important difference, however, is that SEEG-related hemorrhages in eloquent brain regions resulted in lasting neurological deficits. Grid-related subdural hemorrhages did not lead to any long-standing injury. The decision to use hybrid or SEEG should tailor the characteristics of either approach to the localization question(s) for a given patien.

• Publisher: Wolters Kluwer Health, Inc
• Subject: Convulsions & seizures / Electrodes / Localization / Neurosurgery / Surgical techniques